This isn't a startup and I honestly don't want to treat it like a business. However, I do think it qualifies as a hack because of how it works. It uses Google Suggest in addition to a dictionary to try to guess the next word that the user is going to type. If you type WHERE, the next word is most probably going to be IS, THE, or DID. If you then select IS, the next word after WHERE IS will probably be THE or MY. KType uses this and a few such principles to make smarter, better guesses. It is not perfect but I intended to make it extremely smart and customized per user. When I was actively working on this, I had 100 ideas per day on how it could basically read the user's mind and suggest words and phrases most effectively.
My family and I looked at many existing systems for making typing easier but there wasn't anything out there so I decided to roll our own. As of right now, I don't know where to go with this because of my cousin's uncertain health condition. I would love to hear from medical and text hackers about developing this further.
Note: Currently I use Google Suggest localized for India so many of the suggestions may seem weird to non-Indian users. However, it's a simple change in URL to get localized suggestions for any country thanks to Google. Also, I wrote it for 1280x1024 resolution but it can be resized for most screen sizes.